Regexp to validate MS SQL uniqueidentifier

I’m working on PHP project that interacts with HRNET and at some point I need to validate if given string is valid mssql guid. For this I use php regular expression:^[0-9a-zA-Z]{8}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{4}-[0-9a-zA-Z]{12}$